PSTAT FINAL|STUDY GUIDE LATEST
VERSION /QUESTIONS AND CORRECT
ANSWERS / A GRADE SCORE
SOLUTION.
68% of the scores that lie on the normal curve are - Answerbetween 1 SD above
and 1 SD below the mean
A z score designates how many standard deviations the raw score is above or below
the mean. T/F - Answertrue
A distribution of test scores is positively skewed. Each of the scores is converted to a z
score. The distribution of z scores is - Answerpositively skewed
Given the following data (4,5,7,9,12,15,18,20), each score is converted to a z score and
then the standard deviation of the z scores are computed. That value is - Answer1
A z score is - Answerdependent upon the mean for computation
Does the z transformation result in a score having the same units of measurement as
the raw score? - AnswerNo. The z scores are standard scores that make it easier to
compare data
z scores - Answerhave the same shape as the set of raw scores from which they
were transformed
the mean of z scores is equal to 0
the standard deviation of z scores is equal to 1
the z value for raw scores at the mean = - Answer0
correlation - Answerhighest correlation = +/- 1
strong correlation = .80+
medium correlation = .60
weak correlation = .40
no correlation = .00
scatter plot - Answera graph of paired x and y values
, can be both linear and curvilinear
in a positive relationship - AnswerX increases, Y increases
X decreases, Y decreases
When is it preferable to use the Spearman rank order correlation? - Answerwhen
the data are of ordinal scaling
Qualities of Pearson r - AnswerX is cause of Y
the correlation is an accident of sampling
Y is the cause of X
a 3rd variable is the cause of the correlation between X and Y
a correlation between college entrance exam grades and scholastic achievement was
found to be -1.08. On the basis of this, you would conclude that - Answerit was
calculated incorrectly
Linear relationships - Answeralthough all points many not fall on the line, a straight
line best categorizes the relationship
a linear relationship can be +/-
With an increase in the value for the standard error of estimate, our confidence in the
prediction of Y given x - Answerdecreases
the assumption that all points are distributed normally around the regression line is -
Answernormality
the standard deviation of Y values from the regression line is the - Answerstandard
error of estimate
linear regression for prediction - Answerlinear relationships are needed
scores must be representative of the data that created the regression line
predictions can only be made from scores falling within the range used to form the
regression line
the assumption of homoscedasticity is valid when - Answerthe variability of Y is
constant across x values
E(Y - Y')^2 - Answerthe total error of prediction
if sy/x x=0.00 the relationship between the variable is - Answerperfect
VERSION /QUESTIONS AND CORRECT
ANSWERS / A GRADE SCORE
SOLUTION.
68% of the scores that lie on the normal curve are - Answerbetween 1 SD above
and 1 SD below the mean
A z score designates how many standard deviations the raw score is above or below
the mean. T/F - Answertrue
A distribution of test scores is positively skewed. Each of the scores is converted to a z
score. The distribution of z scores is - Answerpositively skewed
Given the following data (4,5,7,9,12,15,18,20), each score is converted to a z score and
then the standard deviation of the z scores are computed. That value is - Answer1
A z score is - Answerdependent upon the mean for computation
Does the z transformation result in a score having the same units of measurement as
the raw score? - AnswerNo. The z scores are standard scores that make it easier to
compare data
z scores - Answerhave the same shape as the set of raw scores from which they
were transformed
the mean of z scores is equal to 0
the standard deviation of z scores is equal to 1
the z value for raw scores at the mean = - Answer0
correlation - Answerhighest correlation = +/- 1
strong correlation = .80+
medium correlation = .60
weak correlation = .40
no correlation = .00
scatter plot - Answera graph of paired x and y values
, can be both linear and curvilinear
in a positive relationship - AnswerX increases, Y increases
X decreases, Y decreases
When is it preferable to use the Spearman rank order correlation? - Answerwhen
the data are of ordinal scaling
Qualities of Pearson r - AnswerX is cause of Y
the correlation is an accident of sampling
Y is the cause of X
a 3rd variable is the cause of the correlation between X and Y
a correlation between college entrance exam grades and scholastic achievement was
found to be -1.08. On the basis of this, you would conclude that - Answerit was
calculated incorrectly
Linear relationships - Answeralthough all points many not fall on the line, a straight
line best categorizes the relationship
a linear relationship can be +/-
With an increase in the value for the standard error of estimate, our confidence in the
prediction of Y given x - Answerdecreases
the assumption that all points are distributed normally around the regression line is -
Answernormality
the standard deviation of Y values from the regression line is the - Answerstandard
error of estimate
linear regression for prediction - Answerlinear relationships are needed
scores must be representative of the data that created the regression line
predictions can only be made from scores falling within the range used to form the
regression line
the assumption of homoscedasticity is valid when - Answerthe variability of Y is
constant across x values
E(Y - Y')^2 - Answerthe total error of prediction
if sy/x x=0.00 the relationship between the variable is - Answerperfect
